The term transidentities, which appeared in Germany in the early twentieth century, refers to a series of practices for identifying with a gender different from the one assigned at birth. The definition of transidentities is located at the intersection of medical discourse, legal dictates, and social practices. Medical and surgical progress since the first third of the twentieth century have made sex change possible, which depending on the country can include a therapeutic dimension and be accompanied by a change in civil status. Transidentities became more visible beginning in the 1960s, doing so at different paces according to the national political context. Medical and legal measures were adopted to take into account the demands made by “trans,” often under pressure from new international norms. Associations were created in the 1990s and Europeanized in order to depsychiatrize transidentity, and found an ally in the European Court of Human Rights for changing national legislation.